JP3160973B2 - Recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for VTR, DAT and the like.

[0002]

2. Description of the Related Art In a so-called 8-mm system VTR,
For example, an index (detection) signal for detecting a position of a desired recording signal can be recorded in a search mode. That is, FIG. 5 schematically shows the main part of the recording format of the 8 mm system VTR. In this figure, a recording area for an index signal is provided between a recording area for a video signal and a recording area for a digital audio signal.

Here, the index signal needs to be recorded and erased during reproduction of, for example, a video signal and a digital audio signal. Therefore, when recording and erasing the index signal, the apparatus in the normal reproduction mode is set to the recording mode only during the period when the recording / reproducing head scans the recording area of the index signal. An index signal or an erasing signal is supplied to the head so that recording or erasing is performed by so-called overwriting.

In such an 8 mm type VTR, recording and reproduction of a magnetic tape are performed at a standard transfer speed (SP) and a lower transfer speed (LP). In this case, the track pattern on the magnetic tape is changed, and particularly the recording track width is changed. That is, in FIG. 6, A indicates a track pattern when recorded at a standard transport speed (SP), and B indicates a track pattern when recorded at a slow transport speed (LP).

On the other hand, the standard transfer speed (S
An apparatus that performs recording and reproduction at a low transfer speed (LP) with a single set of heads has been implemented. In such an apparatus, for example, a head having a recording / reproducing width corresponding to a recording track at a low transport speed (LP) is used. Therefore, the track pattern in this case is as shown in FIG. 7, for example. That is, A in FIG.
P shows a track pattern when recorded at P), and B in the figure shows a track pattern when recorded at a low transport speed (LP). Here, in a track pattern recorded at a standard transport speed (SP), a non-recorded area (guard band) is formed between each track.

However, in such an apparatus, for example, a magnetic tape recorded by an apparatus having a dedicated head at a standard transfer speed (SP) may be reproduced. In this case, the relationship between the track pattern and the head is as shown in FIG. The broken line in the figure indicates the scanning locus of the head. Here, the reproduction of the video signal, the digital audio signal, and the index signal is performed without any trouble.

However, in such an apparatus, it may be necessary to delete the index signal. In this case, when a specified erasing signal is supplied to the dual-purpose head and erasing is performed, the range of the scanning trajectory of the head indicated by the broken line in the figure is erased, but the range corresponding to the above-described guard band on both sides is eliminated. It will be erased. For this reason, for example, when an attempt is made to detect a desired index signal in the search mode, there is a possibility that an unerased index signal is detected and a malfunction occurs.

When recording a video signal and a digital audio signal, the preceding erasure is performed by an erase head wider than the track width in the case of recording at a standard transfer speed (SP), so that the above-mentioned unerased portion does not occur. . Therefore, the above-mentioned remaining problem is, for example, a standard transfer speed (SP).
The magnetic tape recorded by the special head is reproduced by the head having both the standard transfer speed (SP) and the low transfer speed (LP), and the index signal is recorded and erased only when the magnetic tape is recorded and erased.

[0009]

The problem to be solved is that a magnetic tape recorded by a dedicated head having a standard transport speed (SP) can be used to transfer a magnetic tape having a standard transport speed (SP) and a low transport speed (LP). When reproducing with the dual-purpose head and recording and erasing the index signal, the scanning trajectory range of the head is recorded and erased, but the range on both sides is left unerased. When trying to detect a signal, a signal left unerased may be detected and cause a malfunction.

[0010]

According to the present invention, there is provided a head 2a, 2b having a recording / reproducing width smaller than a track width at a standard speed.
In the recording / reproducing apparatus using the method, when the recorded magnetic tape 1 is reproduced and the detection signal recorded on the reproduction track is processed (circuit 9), the detected signal is supplied to the head at least when the detection signal is erased. A means (amplifier 24, switch 11) for increasing a current value only when the processing is performed at the standard speed.

[0011]

According to this, by increasing the current value supplied to the head when the detection signal is erased, the range on both sides of the scanning trajectory of the head is also erased, and the remaining signal is detected to cause a malfunction. You can eliminate fear.

[0012]

FIG. 1 shows the construction of a so-called 8-mm system VTR. In this figure, reference numeral 1 denotes a magnetic tape, and the magnetic tape 1 is wound around the rotary head 2 over a range of 180 ° or more. Then, the digital audio signal is recorded and reproduced in a range where the winding is made larger than 180 °.

Therefore, at the time of recording, first, a signal from the video input terminal 3 is supplied to the recording processing circuit 4. The signal from the recording processing circuit 4 is supplied to switches 5a and 5b, and the switches 5a and 5b alternately select the signals for each field and distribute the signals to two channels. The signals from the switches 5a and 5b are respectively supplied to the recording amplifiers 6a and 6a.
6b, are supplied to the two heads 2a, 2b of the rotary head 2 through the recording control switches 7a, 7b.

A signal from an audio input terminal 8 is supplied to a digital processing circuit 9. This digital processing circuit 9
5a, 5b through an FM modulator 10, usually a switch 11, which is switched to the illustrated side.
Supplied to The switches 5a and 5b alternately select the signals for each field and distribute the signals to a channel opposite to the above-described video signal.

Reference numeral 12 denotes a spindle motor for driving the rotary head 2, and reference numeral 13 denotes a capstan motor for transferring the magnetic tape 1. The spindle motor 12 and the capstan motor 13 are servo-operated by a servo circuit 14, respectively. At the time of recording, the recording processing circuit 4
Supplies the synchronizing signal of the input video signal to the servo circuit 14, drives the motors 12 and 13 in synchronization with the input video signal, and controls the switching of the switches 5a and 5b.

On the other hand, during reproduction, signals from the two heads 2a and 2b of the rotary head 2 are supplied to the switch 16 through reproduction amplifiers 15a and 15b, respectively.
The switch 16 is switched by the servo circuit 14 every time the rotary head 2 rotates by 180 °, and the video signals distributed to the two channels are continuously taken out. The signal from the switch 16 is supplied to the reproduction processing circuit 17, and the signal from the reproduction processing circuit 17 is supplied to the video output terminal 1.
It is taken out to 8. Note that a control signal in the reproduced video signal is supplied from the reproduction processing circuit 17 to the servo circuit 14, and the driving of the capstan motor 13 is controlled by the control signal to perform tracking control.

Signals from the reproducing amplifiers 15a and 15b are supplied to a switch 19, and the switch 19 is switched by the servo circuit 14 to a side opposite to the switch 16 every time the rotary head 2 rotates by 180 °. The signal from the switch 19 is supplied to the digital processing circuit 9 through the FM demodulator 20, and the signal from the digital processing circuit 9 is taken out to the audio output terminal 21.

Reference numeral 22 denotes a mode control circuit, which operates in accordance with an operation signal from the operation display panel 23, such as recording, reproduction, search, and an operation mode such as a standard transfer speed (SP) or a lower transfer speed (LP). Is determined. Then, a signal from the mode control circuit 22 is supplied to the servo circuit 14, and control according to the determined operation mode is performed.
Further, predetermined processing is performed in the digital processing circuit 9.

In this apparatus, when recording an index (detection) signal in the recording or reproduction mode, the operation display panel 23 is operated. As a result, the operation signal is supplied to the digital processing circuit 9 through the mode control circuit 22, and a predetermined index signal is formed and recorded in a predetermined period of the magnetic tape 1. In the reproduction mode, recording is performed by turning on the switches 7a and 7b only for a predetermined period.

In the search mode using the index signal, a reproduced signal being searched is supplied to the digital processing circuit 9. When the predetermined index signal is reproduced, the detection signal is supplied to the servo circuit 14 through the mode control circuit 22, and the transfer of the magnetic tape 1 is stopped.

Further, when erasing the index signal in the reproduction mode, the operation display panel 23 is operated. As a result, the operation signal is supplied to the digital processing circuit 9 through the mode control circuit 22, and a predetermined erase signal is formed. When the switches 7a and 7b are turned on only during the recording period of the index signal, the magnetic tape 1 is turned on.
Is erased for a predetermined period.

Further, in this apparatus, when the magnetic tape 1 is recorded at the standard transfer speed (SP), the reproduction processing circuit 17 and the servo circuit 14 detect it. When the index signal is to be erased from the magnetic tape 1 recorded at the standard transfer speed (SP), the switch 11 is switched in the opposite direction as shown in FIG.
The erasure signal from the digital processing circuit 9 is amplified by the amplifier 24 to, for example, three times the level so that erasure is performed.

That is, in this apparatus, when recording and erasing the index signal in the reproduction mode, for example, the reproduction signals from the heads 2a and 2b shown in FIGS. , D as shown in FIG.
a and 7b are turned on. The recording signal of the index signal is, for example, 5.8 MHz and 2.10 MHz as shown in FIG.
The erase signal is formed by a 9-MHz single-wave FM signal, and the continuous signal of, for example, 5.8 MHz as shown in FIG. When the index signal is erased when the magnetic tape 1 is recorded at the standard transfer speed (SP), the erase signal is amplified to, for example, three times the level as shown in FIG. .

Accordingly, in this apparatus, when reproducing the magnetic tape recorded by the apparatus having a dedicated head having a standard transfer speed (SP) as shown in FIG. Is amplified on both sides of the head 2a or 2b by amplifying it to, for example, three times the level, and erasing is performed up to both sides of the scanning trajectory of the heads 2a and 2b.

In this way, according to the above-described apparatus, the current value supplied to the heads 2a and 2b at the time of erasing the detection signal is increased (amplifier 24), so that the range on both sides of the scanning locus of the head is also erased and unerased. It is possible to eliminate the possibility that a malfunction occurs due to the detection of the detected signal.

In the above-described apparatus, the recording of the index signal is performed at a prescribed level. In this case, even if there is a portion that is not recorded on both sides of the scanning trajectory of the heads 2a and 2b, reproduction and detection can be performed without any problem. In addition, the magnetic tape 1 is moved to a standard transfer speed (S
In the case of recording in P), guard bands are generated on both sides of the scanning trajectory, so there is no problem even if erasing is performed at three times the level.

Further, this apparatus can be applied to a DAT or the like in which a digital signal is recorded and reproduced using a rotary head.

[0028]

According to the present invention, by increasing the current value supplied to the head when the detection signal is erased, the range on both sides of the scanning trajectory of the head is also erased, and the remaining signal is detected. The possibility of malfunctioning can be eliminated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a timing chart for the explanation.

FIG. 3 is a waveform diagram of a signal for the explanation.

FIG. 4 is a diagram showing a track pattern for the explanation.

FIG. 5 is a diagram for explaining an index signal.

FIG. 6 is a diagram for explaining a track pattern.

FIG. 7 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 magnetic tape 2 rotating head 2a, 2b head 3 video input terminal 4 recording processing circuit 5a, 5b, 11, 16, 19 switch 6a, 6b recording amplifier 7a, 7b recording control switch 8 audio input terminal 9 digital processing circuit 10 FM modulation Device 12 Spindle motor 13 Capstan motor 14 Servo circuit 15a, 15b Reproduction amplifier 17 Reproduction processing circuit 18 Video output terminal 20 FM demodulator 21 Audio output terminal 22 Mode control circuit 23 Operation display panel 24 Amplifier

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/00-5/024 G11B 15/087 101 G11B 20/00

Claims (1)

(57) [Claims] In a recording / reproducing apparatus using a head having a recording / reproducing width smaller than a track width of a standard speed, when reproducing a recorded magnetic tape and processing a detection signal recorded on the reproducing track, A recording / reproducing apparatus provided with means for increasing a current value supplied to the head at least when the detection signal is erased only at the time of processing at the standard speed.